Lorrene Davis Ritchie, PhD, RD¹, Allen W. Knehans, PhD², Alexandra Evans, PhD, MPH³, Kristine Kelsey, PhD, RD⁴, Dana E. Gerstein, MPH, RD⁵, Gail M. Woodward-Lopez, MPH, RD¹, and Patricia B. Crawford, DrPH, RD⁶. (1) Center for Weight and Health, University of California, Berkeley, 9 Morgan Hall, Berkeley, CA 94720-3104, 510-489-8483, ritchie25@earthlink.net, (2) Department of Nutritional Sciences, Health Sciences Center, The University of Oklahoma, P.O. Box 26901, Oklahoma City, OK 73190, (3) Norman J. Arnold School of Public Health, University of South Carolina, Department of Health Promotion and Education, Health Sciences Building, Columbia, SC 29208, (4) University of North Carolina at Chapel Hill, Center for Development and Learning and Department of Nutrition, 1450 NC Highway, Chapel Hill, NC 27599, (5) Center for Weight and Health, Unversity of California, Berkeley, 3 Giannini Hall, Berkeley, CA 94720-3100, (6) Department of Nutritional Sciences and Center for Weight and Health, University of California, Berkeley, 9 Morgan Hall, University of California, Berkeley, Berkeley, CA 94720-3104

PURPOSE: It would be informative to know whether meal and snack patterns have independent effects on adiposity. A comprehensive review of the scientific literature was undertaken to assess and summarize the latest knowledge regarding the role of meal and snack patterns as determinants of obesity in children and adults. METHODS: Four lines of evidence were examined: 1) secular trends in intake over the period that the prevalence of obesity has steeply risen; 2) experimental studies that elucidate plausible mechanisms of action; 3) observational studies; and 4) prevention trials that aimed to modify at least one of the determinants of interest. The nature and extent of the evidence regarding the following were summarized: 1) eating frequency; 2) snacking; and 3) breakfast skipping. FINDINGS: With the exception of breakfast skipping, the literature on snacking and meal frequency is minimal, conflicting, and hampered by the fact that there has been little consistency in the way in which meal and snack patterns have been defined. The secular data suggest that snacking has increased while meal eating has decreased. Those who consumed snacks tended to consume more calories, but the extent to which the composition and amount of foods may override any effect of timing of consumption is unclear. Based on the cumulative evidence, breakfast skipping appears to be fairly consistently related to adiposity, although none of the studies reviewed can prove a cause-effect relationship. No conclusive statement can be made at present with respect to the relationship between snacking and eating frequency and obesity.

Learning Objectives: